Fluid metering and dispensing valve having flexible trap chamber



United States Patent [72] Inventor Frank A. Babin Chicago, Ill. 21 'Appl. No. 791.564 [22 Filed Jan. 16, 1969 [45] Patented Dec. 29, 1970 [73] Assignee SCM Corporation v New York, N.Y. a corporation of New York [54] FLUID METERING AND DISPENSING VALVE HAVING FLEXIBLE TRAP CHAMBER l I Claims, 12 Drawing Figs.

[52] U.S. Cl 222/207, 222/355, 222/361, 222/493 [5 I] Int. Cl G01fI1/02 [50] Field ofSearch 222/207, 213, 305, 336, 355, 361,407, 449, 450, 451, 453, 445, 490, 493, 4, 496, (Inquired) [56] References Cited V UNITED STATES PATENTS 2,628,004 2/1953 Schlicksupp 222/493 2,71 1,271 6/1955 Schlicksupp 222/493 3,134.514 5/1964 Booth 222/207 Assistant ExaminerDavid A. Sherbel Attorneys-Gerald'S. Schur and Keith D. Moore ZZZ/493 ABSTRACT: A dispenser is fastened in the mouth of an inverted container for dispensing predetermined quantities of liquid therefrom, and includes a housing having a cylinder which opens externally of the container and has disposed therein a movable valve member with a flexible diaphragm portion. An inlet port provides fluid communication between the interior of the container and the cylinder, and the valve member has a chamber for receiving liquid from the container. Movement of the valve member in one direction in the cylinder closes the inlet port and flexes the diaphragm portion to reduce the volume of the chamber. Upon flexing of the diaphragm portion. a normally closed discharge valve opens to permit fluid to flow from the chamber in response to the reduced chamber volume. The movement of the valve member, subsequent to the closure of the inlet port, is limited by stop means so as to limit the reduction in the chamber volume and thereby control the quantity of fluid dispensed. Movement of the valve member in the opposite direction extends the diaphragm portion, closes the discharge valve, and opens the inlet port to enable fluid to flow into the chamber.

PATENTEDDECZQIQYG 3550,81?

SHEET 1 [IF 2 FRANK A. ABIN This invention relates to fluid dispensers, and more particularly to dispensers for use in photocopying machines wherein small quantities of liquid are dispensed from sealed airtight containers, e.g. bottles, by sudden short-stroke movements imparted to the containers.

In an electrostatic-copying process, a latent electrostatic image is developed into a visible image by particles having an electrical charge whichare attracted to the opposite charge of the electrostatic image. When the latent image is developed by a liquid process, the charged particles are contained in a carrier liquid, for example a dispersant, and such liquid-particle combination is generally referred to as a liquid toner. To properly develop the latent image, the concentration of the charged particles in the liquid toner must .be maintained at an optimum level.

in an electrostatic-photocopying machine using a liquid process, a latent image bearin g surface is brought into contact with liquid toner having substantially the desired concentration of charged particles for proper development of the latent image; As the particles are removed from the liquid toner by the development of successive latent images, the concentra tion of the liquid toner decreases and it bedomes necessary to replenish the liquid toner with anadditional quantity of charged particles so as to maintain substantially the optimum concentration. The replenishment is conveniently accomplished by adding to the liquid toner a small quantity of carrier liquid having a much higher concentration of charged particles than the optimum concentration of liquid toner, so as to increase the concentration of the particles in the liquid toner. The liquid carrier, having such a high concentration of charged particles, is generally referredto as replenisher.

' Since only a very small quantity of charged particles are normally used to develop a single latent image, the liquid toner is conveniently replenished by' intermittently adding small quantities of replenisher, on theorderjof 1 cc. In addition, the replenishment of the liquid toner is usually controlled automatically by the photocopying machine according to predetermined conditions, and to enable the machine to exercise accurate control of the concentration of charged particles in the liquid toner, substantially substantially same quantity of replenisher must be added at each intermittent interval. Furthermore, it is essential that there be no leakage of replenisher into the liquid toner which would materially affect the concentration of the particles in the liquid developer. Since only about l 'cc. of replenisher is added to the liquid toner at a given time, it is readily apparent that even a small which may be conveniently discarded after the replenisher has been transferred to the liquid toner. Since it is undesirable to replenisher.

In the past, the replenisher has been sold in aerosol cans having a dispenser sealed thereto and containing a propellantvproducing chemical, such as a. fluorochlorohydrocarbon, to

force the replenisher through the dispenser. The aerosol can is inserted into the photocopying machine, and the dispenser is operated by a mechanism in the machine, usually in the form of an electrically actuated solenoid,'whi ch imparts sudden short-stroke movements to, the can to operate the dispenser. However, aerosol cans have been found to be unsatisfactory, because the propellant-producing chemical undesirably affects the replenisher and substantially shortens the period of time within which it may be used, thus reducing the period of timethat the container may be kept in storage. Also. since the replenisher is dispensed under pressure, the dispenser usually has an undesirably small fluid passageway which tends to become clogged. In addition, the propellant-producing che mical occupies a portion of the volume of the container which mightotherwise be used to contain an additional quantity of replenisher, and thus-necessitates more frequent replacement of the containers in the photocopying machine. Furthermore, a dispenser which operates under greater than atmospheric pressure necessitates a container capable of withstanding the pressure generated by the propellant-producing chemical, and such a container is usually more expensive than would be the case if the dispenser operated under atmospheric pressure. Accordingly, an object of the present invention is to provide a relatively inexpensive dispenser which may be sealed into a disposable container for dispensing predetermined quantities of liquid from the container. i 1

Another object of the present invention is to provide a dispenser for connection with the container and which may be inserted into a photocopying machine and operated by the existing mechanism used to operate the aerosol dispensers of the ast.

Still another object of the present invention is to provide a dispenser which maybe sealed toan airtight, unpressurized container for dispensing predetermined quantities of liquid from the container, wherein thequantities of liquid dispensed are in theorder of 1 cc.

An additional object of the present invention is to provide a dispenser which may be sealed to an airtight, inverted container, wherein the dispenser normally blocks all fluid communication to the container and dispenses predetermined quantities of liquid from the container'only in response to shortstroke movements. 4

A further object of the present invention is to provide a dispenser for dispensing predetermined quantities of replenisher for use in a photocopying machine, wherein the dispenser is' constructed so as to not bechem'ically affected by the replenisher and also so as to not undesirably affect the Still other objects, features and advantages,.of the present invention will be apparent to those skilledin the art from a transfer the replenisher in a manner likely to result in spilling,

such as by opening the container and pouring the contents into the machine-the container is usually provided with a dispenser which is sealed into the container and operated by the machine to effect the transfer of the. replenisher. To'

minimize the number of operable parts in the "machine and to enable the replenisher to be dispensed directly into the liquid toner. the dispenser sealed into the container is usually of the type that dispenses the desired predetermined quantity of readingof the following detailed. description of the embodiments of the invention, taken in conjunction with the accompanying drawings, wherein: I

FlG. .1 is exploded perspective view of a preferred embodiment of a fluid dispenser according to the present invention;

.FIG. 2 is a cross-sectional view of the dispenser illustrated in FIG. 1, showing a fluted rod extending through an opening in a valve member;

container must be relatively inexpensive so as to be disposable along with the container. In addition, the containers are often placed into storage for relatively long periods of time prior to their being used. Therefore, it is necessary that the dispenser be constructed so that it will not be chemically affected by the FIG. 2A is a cross-sectional view taken along the lines 2A2A in FIG. 2; I

FIG. 3 is a partial cross section view of the dispenser shown in FIG. 2, illustrating the manner in which the fluid inlet port is closed during the initial portion of the discharge stroke;

FIG. 4 is a partial cross-sectional view of the dispenser shown in F IG. 2, illustrating the condition of the dispenser at the end of the discharge stroke with the valve member' deformed and discharge valve opened;

FIG. 5 is a partial cross-sectional view of another embodiment of the dispenser constructed in accordance with the present invention; p

. HO. 6 is an end view of the dispenser shown in FIG. 5;

FIG. 7 is a partial cross-sectional view of the dispenser shown in FIG. 5, illustrating the condition of the discharge valveof the dispenser at the end of a discharge stroke;

FIG. 8 is a partial cross-sectional view of still another embodirnehtof a dispenser constructed in accordance with the present invention;

FIG. 9 is an end view of the dispenser shown in FIG. 8;

FIG. 10 is a partial cross-sectional view of the dispenser shown in FIG. 8, illustrating the condition of the discharge valve during the final portion of a discharge stroke;

FIG. 11 is a partial cross-sectional view of the dispenser shown in FIG. 8, illustrating the condition of the discharge valve during the initial portion of the intake stroke.

Referring now in detail to the figures of the drawings, in FIGS. 14 there is shown a preferred embodiment of a dispenser, generally indicated at 11, which is constructed according to the present invention for-use in a container 13 which is shown in phantom lines. The dispenser 11 includes a cylindrical cup-shaped housing 15 for insertion into the mouth 13a'of the container 13, with an inboard end 15a protruding internally into the container 13 and anoutboardend 15b ex tending externally from the container 13'. The outboard end ISbhas an annular flange 150 for engaging a rounded lip 13!) on the mouth of the container 13 to position the housing 15 in the container 13. The housing 15 has a cylinder 15d formed therein which is closed at the inboard end 15a by a conicallyshaped wall 15e extending into the cylinder 15d, and open at the outboard end 15b for receiving a valve member 17 which is axially movable along the cylinder 15d. The valve member 17 has an inboard portion 17a in engagement with the cylinder 15d and a reduced outboard portion 17b forming an annular shoulder 17c from which a tapered nozzle 17d extends axially from the housing 15 through the open end of the cylinder 15d.

The cylindrical cup-shaped housing 15 is constructed from a suitable deformation-resistant material which is chemically inert to the liquid in the container 13. One such material is acrylonitrile-butadiene-styrene. The valve member 17 is also constructed from a material which is chemically inert to the liquid in the container 13, but is preferably an elastic, compressible material, such as a synthetic rubber composed of butadiene and acrylon nitrile.

From the housing 15, the tapered nozzle 17d extends through inboard and outboard coaxial bores 19a, 19b respectively, formed in a cylindrical guide member 19 which is received into the cylinder 15d of the housing 15 in a sliding fit for-movement along the axis thereof. The outboard axial bore 19b is tapered for receiving and supporting the tapered nozzle 17d and is interconnected by an annular shoulder 190 to the inboard coaxial bore 19a. The inboard coaxial bore 19a is of a larger diameter than the bore 19b, and receives the outboard portion 17b of the valve member 17 with the shoulder thereof 17c abutting the annular shoulder 190 of the guide member 19. The guide member 19 has an annular flange 19d formed thereon which is received into a cylindrical recess 15f formed in the cylinder 15d. The cylindrical recess 15f forms an annular shoulder 15g for engagement by the flange 19d and serves as a stop to limit the inboard axial movement of the guide member 19.

The guide member 19 is retained in the housing 15, and the housing 15 is fastened to the container 13 by means of a sealing cap 21 having an axial aperture 21a. The sealing cap 21 is placed over the outboard end 1511 of the housing 15 with the guide member 19 being received through the axial aperture 21a. and with the cap 21 abutting the flanges 19d, 15c of the guide member 19 and the housing 15 respectively. In addition, a cylindrical flange 21b is formed around the axial aperture 214 on the outboard side of the sealing cap 21 for supporting andguiding the guide member 19 during axial'movement in the cylinder 15d. A compressible ring-shaped seal member 23 is placed on the inboard side of the annular flange 15c of the housing 15, and the housing 15 is clamped in fluid-sealing relation to the rounded lip 13!) of the container 13 by crimping the edge of the sealing cap 21 against the lip 13b and compressing the ring-shaped seal member 23 therebetween.

The guide member 19 is constructed from a suitable materi which is inelastically deformable and desirably chemically inert from the liquid in the container 13., even. though the cap 21 will'ordinarily not come into contactyvith the liquid.

The inboard portion 17a of the resilient valve memberg117 has an external O-ring l7e formed thereon-which is circurn ferentially compressed in the cylinder so as to v be deformably pressed in fluid-sealing relation against the wall of the cylinder. The valve member 17 has a chamber 17fformed.

therei'niwhijch opens toward the inboard end of the cylinder 15a' for receiving liquid, and fluid communication isprovided with the liquid in the container 13 by a port 1511 formed inthe housing 15 which opens into the cylinder 15d adjacent to the end wall l5e. In the illustrative embodiment, the fluid inlet port 15h is in the form of a segmented annular opening. The I inboard portion 17a of the resilient valve member l7.-se rves as a closure portion for closing the fluid inletport 15h-f, and the fluid communication between the container 13. and the chamber 17f may be interrupted, as shown in FIG}, bymoving the end of the inboard portion 17a past .the port .15 h and pressing it in fluid-sealing relation against the end. wall l5e.

The quantity of liquid dispensed by thedispenser 11 is determined by varying the volume of the chamber 17f between maximum and minimum limits.v To enablethe volume v of the chamber 17f to be varied, the elastically deformable valve member 17 is provided with aflexible'diaphragm 17g- I which is formed between the inboard and outboard portions 15a, 15b by a portion of reduced wall thickness. The volume,

of the chamber 17f is normally at a maximum limit with the diaphragm 17g in an extended position as shown in FIGS. 2

and 3, but may be reduced to a minimum limit by flexing the I diaphragm 17g. As more particularly shown in FIG. 4, the diaphragm portion 17g is flexed by moving the guide member 19, and hence the valve member 17, axially inboard along the cylinder 15a, with the inboard end of the valve member 17 pressed against the end wall 152 of the housing 15. To facilitate the inboard movement of the guide member 19, the inboard edge 19e of the guide member 19 may desirably be chamfered outwardly so as to cam the flexing diaphragm 17g into the inboard bore 19a during axial movement of the guide member 19. The flexing of the diaphragm 17g, and hence the reduction in the volume of the chamber 17f, to a minimum limit is controlled by the engagement of the flange 19d onthe guide member 19 with the shoulder 15g formed in the cylinder 15d.

To enable liquid to flow from the dispenser 11 upon reduc tion in the volume of the chamber 17f, the dispenser 11 is provided with a discharge valve, generally indicated at 25, which is normally closed to prevent leakage, but opens upon flexing the diaphragm portion 17g to permit liquid to flow from the chamber 1717f. In the preferred embodiment, the discharge valve 25, includes an axial port 1712 formed in the end of the nozzle 17d, and a fluted rod 27 which is axially positioned in the cylinder 15d with an inboard end 27a being received in an interference fit in an axial bore 151' formed in the conicallyshaped wall 15e of the housing 15. As shown in FIG. 2, the fluted rod 27 has a cylindrical portion 27b formed on the outboard end which extends in fluid-sealing relation through they axial port 17h to prevent liquid from flowing from the chamber 17f through the port 17h. As shown in FIG. 4,'flexing of the diaphragm portion 17g, by the inboard axial movement of the valve member l7, m oves the port 17h axially along the fluted rod 27 from the cylindrical portion 27b onto a fluted portion 270, thereby providing openings for the liquid to pass from the chamber.

The fluted rod 27 is constructed froma suitable deformation-resistant material which is chemically inert to the liquid in the container 13. The fluted rod 27 is desirably constructed from acetal. although it may also be constructed from the same material as the housing 15.

Normally, the chamber 17f is maintained filled with liquid to the maximum limit by a resilient biasing means, generally indicated at 29, which urges the valve member 17 away from the closed end of the cylinder d and thus maintains the discharge valve means closed and the fluid inlet port 15e open to permit liquid from the container 13 to fill the chamber 17f. In the illustrative embodiment, the resilient biasing means 29 is in the form of a coiled tension spring 31 disposed about the fluted rod 27 with one end engaging a bracket 15] at the end wall 15e of the housing 15 which axially positions the spring 31 in the cylinder 15d. The spring 31 is'const'ructed from steel, and the bracket 15] maydesirablybe formed integrally with the end wall 15e of the housing 15. Theopposite end of the spring 31 is received into a retaining cup 33 having an axial opening 33a through which the fluted rod 27 extends. The cup 33 is disposed in a cylindrical recess 17i formed inboard from the nozzle I74 in the reduced end portion 17b of the valve member 17. The retaining cup 33 is constructed from the same material as the housing 15 and prevents the spring 31 from becoming embedded in the valve member 17. The upper edge 33b of the cup 33 may desirably be chamfered inwardly to serve as a cam to prevent the spring 31 from bind ing during the inboard axial movement of the valve member 17 in the cylinder 1511-. e

In operation, a small predetermined-quantity of fluid may be dispensed from the container 13 by imparting a short discharge stroke to either the container 13 or the guide member 19 to cause a relative reciprocal motion between the housing 15 and the valve member 17 which moves the valve 1 container 13 to enable an additional quantity of liquid to flow into the chamber 17f in preparation for the-dispensing of another predetermined quantity of liquid therefrom.

Another embodiment of a dispenser constructed according to the present invention is shown in FIGS. 5-7. With the exception of the discharge valve means 25, the dispenser 11' in this embodiment isgenerally identical to the dispenser 11 described in the previous embodiment, and accordingly identical reference numerals have been placed on identical portions thereof. In this embodiment, the dispenser 11' has a discharge valve 25 which includes a normally closed port 1711 and a tube 35. As more particularly shown in FIG. 6, the port 17h is composed of flaps 17j which are formed by slits 17k in the'end of the nozzle 17d of the valve member 17. The tube 35 has an inboard end 35a disposed in the axial bore 151' of the housing 15 and extends along the cylinder 15d in the same manner as the fluted rod 27 in the previous embodiment,

but terminates short of the normally closed port 17h. The

35b of the tube 35 upon flexing of the diaphragm portion 17g member 17 toward the inboard end of the cylinder 15d and compresses the spring 31. During the initial inboard move ment of the valve member 17, the closure portion 17a moves the end wall 15e of the housing '15 to close the fluid inlet port 15!: and interrupt the fluid communication between the interior of the container 13 and the cylinder 15d. Further inboard axial movement of the valve member 17 flexes the diaphragm portion 173, thereby reducing the. volume of the chamber 17f,

and moves the fluid discharge port 17h onto the fluted portion past the fluid inlet port 15h and the open end presses against 17 undergoes an intake stroke in response to the force exerted against it by the compressed spring 31 which returns the valve member 17 to the normal starting position. At the beginning of the intake stroke, the diaphragm portion 17g extends and increases the volume of the chamber 17f, thereby causing a partial vacuum in the chamber 17]: Since the discharge valve 25 is still open, air flows through the valve 25 and into the chamber 17f to fill the increasing volume provided by the extending diaphragm portion 17g. As the air enters the chamber 17f, it moves upward through the tapered nozzle 17d which provides a gradually increasing cross-sectional area that serves to prevent air entrapment in the nozzle 17d.

Further outboard movement of the valve member 17 moves the discharge port 17halong the fluted rod 27 until the cylindrical end portion 27b closes the port 17h to stop the passage of air and prevent leakage of liquid from the chamber 17f. In addition. the inboard end of the valve member 17 moves past the fluid inlet port 15!: to again establish fluid communication between the cylinder and the interior of the container. As the air rises in the chamber 17] it encounters and moves along the protruding conically-shaped end wall 152 of the housing 15 which serves to guide the air to the'fluid inlet port 1511 to prevent air entrapment in the cylinder 15d. From the cylinder 15d, the air passes through the fluid inlet port. 1511 and into the of the valve member 17.

The tube 35 is constructed from a suitable deformation-resistant material which is chemically inert to the liquid in the container 13, such as aluminum; To facilitate the movement of the tube 35 through the normally closed port 17h, the outboard end 35b of the tube 35 may be desirably chamfered.

In operation, the inboard axial movement of the valve member 17 during a dischargestroke brings the flaps 17] of the normally closed valve 25 into contact with the outboard end 35b of the tube 35 and, upon flexing of the diaphragm portion 17g, forces the flaps apart and moves them axially along the tube 35 so as to enable the open end thereof to f protrude externally from the valve member 17, as shown in member 17 during an intake stroke, the extending'diaphragm portion 17g increases the volume of the chamber 17f and produces a vacuum which causes air to flow through the open end 35b of-the tube 35 and out the transverse apertures 35c into the chamber 17f. As the diaphragm 17g extends, the flaps 17] of the normally closed port 17h are moved axially along the tube. 35 until they again close. and cover the open'end 35b of the tube 35 to stop the flow of air into the chamber 17f and prevent leakage of liquid from the chamber 17 f.

Still another embodiment of a dispenser, constructed in accordance with the present invention, isshown in FIGS. 8-1 l.

The dispenser 11" in this embodiment is generally identical to the dispenser ll described in connection with FIGS. 57,

with the exception of the discharge valve means 25", and accordingly identical reference numerals have been placed on identical portions thereof. In this embodiment, the discharge valve 25'. includes only the normally closed flaps 17j in the end portion of the nozzle 17d, as described in the preceding embodiment 11' and shown in FIG. 9. The flaps 17] are adapted to move inwardly and outwardly with respect to the chamber 17f in response to the fluid pressure existing in the chamber 17f upon flexing and extending of the diaphragm portion 17g.

In operation, the inboard axial 'movement of the valve member 17 during a discharge stroke flexes thediaphragm portion 17g and reduces the volume of the chamber 17f. As shown in FIG. 10, the reducing volume of the chamber 17f produces a fluid overpressure therein which forces the flaps of the normally closed discharge valve 25" outwardly from the chamber to enable the liquid displaced bythe reducing volume of the chamber 17f to pass through the valve 25".

creases the volume of the chamber 17f. As shown in FIG. 11, the increasing volume of the chamber 17f produces a vacuum therein which causes the flaps 17j to be drawn inwardly into the chamber and parted so as to admit air into the chamber 17f. As the diaphragm portion 17g becomes fully extended, the resulting vacuum diminishes thereby enabling the flaps l7j to again close to stop the flow of air into the chamber l7fand prevent leakage of liquid therefrom.

-To facilitate the operation of the dispensers described in the foregoing embodiments, an orifice k is provided in the end wall 152 of the housing 15 to enable liquid in the container 13 toenter the chamber 17f in response to the vacuum formed therein during the initial portion of an intake stroke to increase the speed of the movement of the valve member 17 in the cylinder 15d during the intake stroke. Also, indentations 19f are formed in the edge of the flange 19d of the guide member 19 and an orifice 21c is formed in the sealing cap 21 to provide passageways through which air may pass in response to the reciprocal movement of the guide member 19 in the cylinder 15d. Furthermore, although not illustrated, an annular recess may be formed in the end wall He of the housing 15 for receiving the resilient inboard end of the valve member 17 and preventing it from circumferentially expanding into the fluid inlet port 15h in response to the fluid overpressure created in the chamber 17f, so as'to ensure the inboard portion 17a of the valve member 17 forming a fluid seal with the end wall l5e of the housing 15.

While only a limited number of embodimentshavebeen illustrated and described, it will be apparent to those skilled in the art that various modifications and improvements may be made without departing from the scope and spirit of the invention. Accordingly it is to be understood that the invention is not to be limited by the illustrative embodiments, but only by the scope of the appended claims.

I claim:

1.. A dispenser for dispensing by gravity a predetermined quantity of fluid from a container comprising a housing for connection with the container, said housing having a cylinder formed therein and a fluid communication port formed therethrough for providing fluid communication between the container and said cylinder, a valve member disposed in said cylinder for reciprocalmovement substantiallyalong the axis thereof, said valve member being sliclably disposed in fluidsealing relation to said cylinder wall and having a chamber formed therein with an opening adjacent said fluid communi-,

cation port for receiving fluid from the container, said valve member having a closure portion adjacent said chamber opening for closing said fluid communication port in response to movement of said valve member in a first axial direction, said valve member having a flexible diaphragm portion adjacent said closure portion for flexing in response to further axial movement of said valve member in said first direction to reduce the volume of said chamber and for extending in response to movement in a second opposite axial direction to increase the volume of said chamber, discharge valve means in said valve member for controlling passage of fluid from said chamber, said discharge valve means being normally closed to prevent passage of fluid there through and operable upon flexing of said diaphragm portion to open and permit fluid to pass from said chamber, and stop means for limiting the movement of said valve member in said first axial direction subsequent to the closure of said fluid communication port to limit the reduction in volume of said valve chamber by the flexing of said diaphragm portion to a predetermined amount.

2. A dispenser according to claim 1, wherein said valve member includes a resilient portion extending across said cylinder and spaced from the opening of said chamber, and said discharge valve means comprises a fluted rod fixedly disposed in said housing and extending substantially parallel to the axis of said cylinder, an annular port formed in said resilient portion of said valve member in axial alignment with said fluted rod, said fluted rod having a cylindrical end portion extending in fluid-sealing relation through said annular port,

said annular port being moved along said fluted rod from said cylindrical end portion onto fluted portion upon flexingof said diaphragm to provide an opening for fluid to pass from said chamber, and said portfbeing moved onto said cylindrical of said cylinder, a port formed insa id; resilient portion of said f valve member in axial alignmen t with said tube by slits dfin ing flaps which are normally closed in fluid-sealing relatio n to each other to prevent passage of fluid from said chamber. said tube havingan open end'adjacent said flapsandfintermedia'te apertures to enable fluid to fl'ow through theopenend of said tube, said normally closed flaps being forcedonto said tube adjacent said open end and pressed outwaidly from said chamber upon flexing of saiddiaphragm portion to enablefluid to pass through said aperturesand out of the open end of i said tube in responseto fluid overpressure in said chamber caused by the reducing volume of said chamber, and said flaps being moved along said tube upon, extension of said diaphragm portion to enable said flaps to close and cover the open end of said tube.

4. A dispenser according to claim 1, wherein saidvalve, member includesa resilient portion elxtendingfacross saidcylinder and spaced from the opening of said chamber, and

said discharge valve comprises a port formed in said resilient portion of said valve member by slits defining flaps, said flaps being normally closed in fluid-sealing relation toeach other to prevent leakage of fluid from'saidchaniber and being adapted to bend inwardly and outwardlyof said chambje' rlto provide an I opening for passage offluidQ from said chamber, said flaps being forced outwardly upon flexing of said diaphragm portion in response to a fluid overpressure in said chamber caused: by the reducing volume of said'chamber, and said flaps being forced inwardly upon extension of said diaphragmpottion in response to a vacuum in said chamber'caused by the increasing volume of said chamber.

5. A dispenser according to claim 1, whereinisaid housing has an end wall across said cylinder for engagement by said ,j

valve member upon movement in said cylinder in said: first axial direction,'said fluid inlet port extending through said wall} portion defining said cylinder and opening into said cylinder I adjacent to said end wall, and wherein said closure portion of said valve member includes a resilient O-ring for' forming a fluid seal with said cylinder and a resilient end portion for engaging said end wall, said resilient O-ring being compressably I disposed in said cylinder and deformably pressed in fluid-sealing relation against the wall of said cylinder, said end portion being deformably pressed in fluid-sealing relation against: said end wall upon movement of said valve member in saidfir'st axial direction, and said 'end portion being spaced from said O- ring so as to span said fluid inlet port and interrupt 'fluid' c'ommunication between the container and the cylinder upon flexing of said diaphragmportion of said valve member.

6. A dispenser according to claim 5, further comprising resilient biasing means for urging said valve member in said' second axial direction-to'maintain said fluid inlet port open"? and said discharge valve means closed.

7. A dispenser according to claim 6, wherein said resilient f biasing 'means includes a coiled spring disposed in said cylinder and engaging said end wall and saidvalve member.

8. A dispenser according to'claim 5, wherein said valve member is formed from a resilient material, and said flexible diaphragm portion'is formed adjacent said O-ring by'a portion" of reduced wall thickness.-

9. A dispenser according to claim 8, wherein said chamber formed in said valve member extends axially from said closure 1 portion with a diminishing cross-sectional area, and said end wall of said housing protrudes conically into said chamber.

10. A dispenser according to claim 8, further comprising a cylindrical guide member disposed in said cylinder for movement along the axis thereof, said guide member having an axial bore formed therein for receiving and carrying a portion cylinder.

11. A dispenseraccording to claim 10, wherein said stop of said resilient valve member during'movement in said for engaging said annular shoulder upon axial movement of said guide member in said first axial direction 

